Recent species in old Islands : the origin of introduced populations of Litoria aurea (Anura : Hylidae) in New Caledonia and Wallis

New Caledonia is a megadiverse tropical island in the southwest Pacific, however, inhabited by only one species of amphibian, Litoria aurea (Hylidae). We used both molecular (CO1 and ND4 gene sequencing) and morphometric data to explore its geographical origin and timing of colonisation. We tested whether this species arrived through transoceanic dispersal before human arrival in the island, or recently through anthropogenic introduction. We found a weak phylogeographical structure within this species, and lower haplotype diversity in New Zealand, New Caledonia and Wallis compared to Australia. No significant genetic differentiation was found between pairs of populations in New Caledonia and Wallis, or between pairs of population from these two islands. We observed a high level of morphometric differentiation between Australian and island populations, and a low level of morphometric differentiation between island populations. Our results support an Australian origin for insular frogs. The possibility of a trans-marine dispersal from Australia to New Caledonia and/or Wallis in-between the Eocene and the Pleistocene cannot be favoured, given the low level of genetic differentiation. Our results are consistent with a recent human introduction, most likely during European times. Our data support the historical absence of amphibians in the old island New Caledonia, and is consistent with the new biogeographical paradigm that this island was totally re-colonized after emergence in Eocene. More studies are necessary to explain the success of this frog in oceanic islands, where it is widespread and abundant, compared to Australia, where it is declining

A new insight into the dissociating effect of strontium on bone resorption and formation.

Calcium phosphates are widely used as biomaterials and strontium (Sr) is known to have the ability to modify the bone balance towards osteosynthesis. In the present study we investigated the capacity of Sr-substituted sol-gel calcium phosphate to modify the expression of genes and proteins involved in extracellular matrix synthesis by primary bone cells. We first determined the most effective concentration of strontium using human primary bone cells. Sol-gel biphasic calcium phosphate (BCP) powders were then synthesised to obtain release of the optimal concentration of strontium. Finally, human osteoblasts obtained from explant cultures were cultured in the presence of sol-gel BCP, Sr-substituted BCP (5% Sr-substituted BCP, corresponding to a release of 5 × 10−5 M [Sr2+] under the culture conditions (BCP5%)) and medium containing strontium chloride (SrCl2). Viability, proliferation, cell morphology, protein production and protein activity were studied. We demonstrated that 5 × 10−5 M SrCl2 and BCP5% increased the expression of type I collagen and SERPINH1 mRNA and reduced the production of matrix metalloproteinases (MMP-1 and MMP-2) without modifying the levels of the tissue inhibitors of MMPs (TIMPs). Thus strontium has a positive effect on bone formation

CFTR-KO pigs exhibit altered bone microarchitecture at birth

International audienceBackground: People with cystic fibrosis exhibit growth defects and brittle bones. That observation has been attributed, in part, to malnutrition and chronic pulmonary inflammation. We tested the hypothesis that disrup-tion of the cystic fibrosis transmembrane conductance regulator (Cftr) gene directly affects bone microarchitecture and integrity by studying bone of newborn Cftr-/- pigs. Methods: We examined femoral cortical and trabecular bones of Cftr-/- pigs less than 24 hours after birth using microcomputed tomography (mCT, Skyscan 1076, Bruker). Scans were performed with the following settings: tube voltage, 80 kV; tube current, 0.125 mA; and voxel size, 17 x 17 x 17 mm (x, y, z). Three-dimensional images were reconstructed and analysed using the NRecon GPU version and CTAn (Bruker) software programs, respectively. The cortical bone porosity and structure were defined using a 3.4 mm wide region centered on the middle of the femur. A total of 37 newborn Cftr-/- piglets (24 males and 13 females) and 18 newborn Cftr+/+ piglets (8 males and 10 females) was subjected to mCT scan. Results: Compared to newborn Cftr+/+ pig controls, Cftr-/- femoral bone exhibited significantly lower total volume (TV), bone volume (BV) and bone volume density (BV/TV) but only in females. However, the Cftr-/- bone mineral density (BMD) in trabecular and cortical tissues was signifi-cantly reduced in both sexes, compared to Cftr+/+ piglets. Interestingly, focusing at the porosity of cortical bone in Cftr-/- pigs as a determinant of bone fragility associated with high fracture risk, we observed higher closed porosity with a marked increase of closed pore surface in cortical bone of Cftr-/- pigs (+18.7% for males and +48% for females). These results suggest a lower bone remodelling, lower interconnectivity within the vascular network, and increased bone fragility in Cftr-/- animals. No significant difference was observed in the open cortical porosity, whatever the gender. Conclusion: Altogether, these data highlight the critical regulatory role of CFTR in bone development and maintenance, and suggest that some bone defects in people with cystic fibrosis are likely primary. Acknowledgment: This work was, in part, supported by the Associa-tion French Vaincre la Mucoviscidose

The effect of zinc on hydroxyapatite-mediated activation of human polymorphonuclear neutrophils and bone implant-associated acute inflammation

Hydroxyapatite (HA) is widely used as coating biomaterial for prosthesis metal parts and as bone substitute. The release of HA particles induces an inflammatory response and, if uncontrolled, could result in implant loss. At the inflamed site, the polymorphonuclear cells (PMNs) represent the earliest phagocytic cells that predominate the cellular infiltrate. We have recently proposed that HA wear debris activate polymorphonuclear cells (PMNs) initiating and/or amplifying thereby the acute inflammatory response. Previous studies have shown that activation of monocytes by HA could be modulated by supplementing this latter with the divalent cation, Zinc. The purpose of this work was to investigate the modulation of PMNs activation following exposure to zinc-substituted HA. Our study demonstrate that addition of zinc to HA particles resulted in decreased levels of the pro-inflammatory mediator interleukin-8 (IL-8) and the matrix metallo-proteinase-9. We also show that these changes involve IL-8 receptors (CXCR-1 and CXCR-2)

CFTR-KO pigs exhibit altered bone microarchitecture at birth

International audienceBackground: People with cystic fibrosis exhibit growth defects and brittle bones. That observation has been attributed, in part, to malnutrition and chronic pulmonary inflammation. We tested the hypothesis that disrup-tion of the cystic fibrosis transmembrane conductance regulator (Cftr) gene directly affects bone microarchitecture and integrity by studying bone of newborn Cftr-/- pigs. Methods: We examined femoral cortical and trabecular bones of Cftr-/- pigs less than 24 hours after birth using microcomputed tomography (mCT, Skyscan 1076, Bruker). Scans were performed with the following settings: tube voltage, 80 kV; tube current, 0.125 mA; and voxel size, 17 x 17 x 17 mm (x, y, z). Three-dimensional images were reconstructed and analysed using the NRecon GPU version and CTAn (Bruker) software programs, respectively. The cortical bone porosity and structure were defined using a 3.4 mm wide region centered on the middle of the femur. A total of 37 newborn Cftr-/- piglets (24 males and 13 females) and 18 newborn Cftr+/+ piglets (8 males and 10 females) was subjected to mCT scan. Results: Compared to newborn Cftr+/+ pig controls, Cftr-/- femoral bone exhibited significantly lower total volume (TV), bone volume (BV) and bone volume density (BV/TV) but only in females. However, the Cftr-/- bone mineral density (BMD) in trabecular and cortical tissues was signifi-cantly reduced in both sexes, compared to Cftr+/+ piglets. Interestingly, focusing at the porosity of cortical bone in Cftr-/- pigs as a determinant of bone fragility associated with high fracture risk, we observed higher closed porosity with a marked increase of closed pore surface in cortical bone of Cftr-/- pigs (+18.7% for males and +48% for females). These results suggest a lower bone remodelling, lower interconnectivity within the vascular network, and increased bone fragility in Cftr-/- animals. No significant difference was observed in the open cortical porosity, whatever the gender. Conclusion: Altogether, these data highlight the critical regulatory role of CFTR in bone development and maintenance, and suggest that some bone defects in people with cystic fibrosis are likely primary. Acknowledgment: This work was, in part, supported by the Associa-tion French Vaincre la Mucoviscidose

Evaluation of Cu-substituted-hydroxyapatite potential for control of particles-induced acute inflammatory reaction.

International audienc

Evaluation of Cu2+ doping potential to control the calcium-phosphate particles-induced acute inflammatory response in bone site.

International audienc

The acute inflammatory response to copper(II)-doped biphasic calcium phosphates

International audienceInfection and inflammation are two key features to consider to avoid septic or aseptic loosening of bone-implanted biomaterials. In this context, various approaches to fine-tune the biomaterial's properties have been studied in order to modulate the crosstalk between immune and skeletal cells. Cation-doping strategies for tuning of calcium phosphates properties has been evidenced as a promising way to control the biomaterial-induced inflammatory process, and thus improving their osteoimmunomodulatory properties. Copper(II) ions are recognized for their antibacterial potential, but the literature on their impact on particulate material-induced acute inflammation is scarce. We synthesized copper(II) ions-doped biphasic calcium phosphate (BCP), intended to exhibit osteoimmunomodulatory properties. We addressed in vitro, for the first time, the inflammatory response of human primary polymorphonuclear neutrophils (PMNs) to copper(II) ions-doped or undoped (BCP) powders, synthesized by an original and robust wet method, in the presence or absence of LPS as a costimulant to mimic an infectious environment. ELISA and zymography allowed us to evidence, in vitro, a specific increase in IL-8 and GRO-α secretion but not MIP-1β, TNF-α, or MMP-9, by PMNs. To assess in vivo relevance of these findings, we used a mouse air pouch model. Thanks to flow cytometry analysis, we highlighted an increased PMN recruitment with the copper(II) ions-doped samples compared to undoped samples. The immunomodulatory effect of copper(II) ions-doped BCP powders and the consequent induced moderate level of inflammation may promote bacterial clearance by PMNs in addition to the antimicrobial potential of the material. Copper(II) doping provides new insights into calcium phosphate (CaP)-based biomaterials for prosthesis coating or bone reconstruction by effectively modulating the inflammatory environment